The present invention relates to LED lighting apparatus and particularly relates to an LED driver circuit with stepwise adjustable power and an LED lighting tube.
LED lighting tube is commonly known as light tube or fluorescent tube. Its light source adopts LED as illuminant. Traditional fluorescent tube is also called fluorescent light. The light is provided with a filament on both ends. The light tube is filled with a small amount of argon and mercury vapor. Fluorescent powder is coated on the inner wall of the light tube. Gases between the two filaments emit ultraviolet light when they are conductive, causing the fluorescent powder to emit visible light. LED lighting tube has many advantages. It is commonly used for general lighting and indoor lighting in offices, malls, restaurants, schools, homes, factories and so forth.
An LED lighting tube usually comprises a light cover, LED beads, aluminum substrate, power supply and so forth. At present, there have been LED lighting tubes with SCR dimming, remote controlled dimming and adjustable power. However, since the said LED lighting tubes are additionally provided with dimming circuits, loss also increases, thus reducing power conversion efficiency. Since power conversion efficiency decreases, lumen of the whole LED lighting tubes also decreases. The cost is higher and it is not beneficial for energy-saving and environmental protection.